Device and method for evaluating damage degree of working solution to tight reservoir

A technology for dense reservoirs and working fluids, applied in measuring devices, analysis of suspensions and porous materials, scientific instruments, etc., can solve problems such as permeability testing, unsatisfied Darcy flow characteristics, and unsatisfactory gas pulse methods, etc., to achieve The effect of less experimental parameters and high efficiency

Inactive Publication Date: 2015-07-22
CNOOC ENERGY TECH & SERVICES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] At present, domestic unconventional reservoir damage evaluation still adopts conventional reservoir evaluation technology, and conventional reservoir damage evaluation mainly adopts the People's Republic of China Oil and Gas Industry Standard (SY/T 6540-2002 Drilling Fluid Completion Fluid Damage Reservoir Laboratory Evaluation Method) The reservoir damage evaluation experiment of the working fluid is carried out, that is, the Darcy formula method, and the permeability of unconventional reservoirs is generally lower than 1×10 -3 μm 2 , when using this method, there will be the following problems: First, the seepage of liquid

Method used

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  • Device and method for evaluating damage degree of working solution to tight reservoir
  • Device and method for evaluating damage degree of working solution to tight reservoir
  • Device and method for evaluating damage degree of working solution to tight reservoir

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Embodiment 1

[0052] As shown in Figure 1, this embodiment discloses a device for evaluating the damage degree of the working fluid to the tight reservoir, which is used to evaluate the permeability (1.0-10 -5 )×10 -3 μm 2The degree of damage to the unconventional tight reservoir by the working fluid mainly includes the upstream standard chamber 1, the downstream standard chamber 2, the core holder 3, the confining pressure pump 7, the needle valve 8, the vacuum pump 11, the advection pump 13, the working fluid Intermediate container 14, formation water intermediate container 15, differential pressure gauge 18, confining pressure gauge 19. Wherein, the inlet of the core holder 3 is provided with a core holder inlet control valve 4, and the outlet is provided with a core holder outlet control valve 5; the outlet of the working fluid intermediate container 14 is provided with a working fluid intermediate container control valve 16, and the formation The outlet of the water intermediate cont...

Embodiment 2

[0090] my country's ×× Basin is rich in coalbed methane resources. In order to solve the problem of coal seam collapse in the development process, it is proposed to use a degradable polymer drilling fluid system. In order to test the damage degree of the drilling fluid to the coal seam of the XX mining area in the basin, the device and method of the present invention are used to conduct an evaluation experiment on the damage of the drilling fluid to the coal rock. At the same time, in order to understand the reliability of the experimental results, a comparative test is carried out using the conventional steady-state method . The device that present embodiment adopts is identical with embodiment 1, and the concrete steps of experimental method are as follows:

[0091] Step 1, drill the coal core, vacuumize for no less than 48 hours, and saturate the formation water of the target formation, the size of the coal core is as shown in the table

[0092] 1 shown;

[0093] Table 1 ...

Embodiment 3

[0115] Block ×× is a low-porosity, low-permeability tight gas reservoir. After the gas well is drilled, it can only be established through fracturing. A clean fracturing fluid system is proposed to reduce the damage of fracturing fluid to the reservoir. In order to test the damage degree of the clean fracturing fluid system to the tight gas reservoir in the block, the device and method of the present invention are used to conduct a damage evaluation experiment. The device that present embodiment adopts is identical with embodiment 1, and the concrete steps of experimental method are as follows:

[0116] Step 1, drill the core, evacuate for not less than 48 hours, and saturate the formation water of the target formation, and the core size is shown in Table 5;

[0117] Table 5 × × block core size

[0118] Sample number

Length / cm

diameter / cm

LX-04

6.62

2.55

[0119] Step 2, put the core into the core holder 3, and apply the confining pres...

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Abstract

The invention relates to the technical field of unconventional oil and gas reservoir damage evaluation, and discloses a device and a method for evaluating the damage degree of a working solution to a tight reservoir. The device comprises an upstream standard chamber, a downstream standard chamber, a core holding unit, a confining pressure pump, a needle valve, a vacuum pump, a constant-flux pump, a working solution intermediate container, a formation water intermediate container, a differential pressure gauge, a confining pressure gauge and the like. Evaluation on the damage degree of liquid permeability after a core of the tight reservoir is polluted by the working solution is realized via a differential pressure time variation parameter in a liquid pressure pulse attenuation process by an unsteady-state liquid pulse method; the experimental process efficiency is high; concerned experimental parameters are few; the current low-efficiency method for testing a damage rate of the liquid permeability by a steady-state method can be replaced; effective development of an unconventional oil and gas reservoir is facilitated; and the device and the method have certain popularization prospects.

Description

technical field [0001] The invention relates to unconventional oil and gas reservoir protection technology, in particular to a device and method for evaluating the damage degree of working fluid to tight reservoir. Background technique [0002] Unconventional oil and gas mainly include shale oil and gas, coalbed methane, tight sandstone gas and other resources. Among them, my country's tight sandstone gas has entered the stage of large-scale development, and its output has accounted for one-third of the country's total natural gas output; the scale of coalbed methane development has also increased year by year. [0003] Unconventional reservoirs are characterized by low porosity, low permeability, and high content of clay minerals. Reservoirs are extremely vulnerable to damage from working fluids such as drilling fluids, completion fluids, cementing fluids, and fracturing fluids. Once the damage occurs, it will affect the Gas well productivity, so reservoir protection is on...

Claims

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Application Information

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IPC IPC(8): G01N15/08
Inventor 史斌高波游利军张晓磊康毅力苏延辉江安
Owner CNOOC ENERGY TECH & SERVICES
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